Biodegradable nanostructured composites

ABSTRACT

A highly compatibilized biodegradable composite with high impact strength including: (a) a polymeric matrix having one or more biodegradable polymers; (b) one or more fillers; and (c) free radical initiators are fabricated via one-step reactive extrusion method. An in-situ free radical reaction method of manufacturing the biodegradable composite, including the step of (a) (1) mixing one or more biodegradable polymers and a free radical initiator; (2) melting step (1) thereby manufacturing the highly compatibilized biodegradable matrix. (b) Mixing the composites of step (a) and fillers or second biodegradable polymers, thereby manufacturing the biodegradable composite. Also, nano-blends are successfully prepared in this invention ascribe to the improved compatibility of the different components.

FIELD OF THE INVENTION

The present invention relates to biodegradable nanostructured polymerbiocomposites and methods of making those.

BACKGROUND OF THE INVENTION

The increased environmental concern on landfilling disposal ofnon-biodegradable plastics and sustainable development of petrol-basedpolymers promotes a significant research requirement on developing fullybiodegradable products with high bio-based contents. The developedbiodegradable polymeric materials can be widely used today in differentareas such as packaging, agriculture, automotive, pharmaceutical, andothers [1]. According to their production method, the bioplastic can beclassified as renewable-resource-based such as polylactide (PLA),poly(butylene succinate (PBS), petroleum based such as poly(butyleneadipate-co-terephthalate) (PBAT) and from mixed source such as poly(trim ethylene terephthalate) (PTT). While based on the chemical nature,bioplastics can be defined as biodegradable and non-biodegradable, forexample bio-derived PTT are not biodegradable where as 100%petro-derived PBAT is biodegradable [2]. Our current invention mainlyfocused on fully biodegradable polymer formulations such as PLA, PBS,PBAT, polycaprolactone (PCL), polyhydroxyalkanoate PHA(s), et al. withhigh performance.

Filler reinforced polymer composites have been continuously researchedfor decades because of the reinforcement effects and cost saving.Compostable products based on biodegradable polymers and natural fillersand fibers can be practical candidates to solve the aforementionedproblems: the dependence on petroleum and landfilling waste management.The fillers used in composites researche include, but is not limitedto: 1) perennial grass such as miscanthus fiber, switchgrass and bamboo;2) natural fillers such as talc, nano-cellulose fiber and calciumcarbonate; 3) waste/by-products from agriculture faming and processingindustry such as coffee husk and tea leaves; 4) High-value fillers suchas carbon fibers, carbon nanotubes and graphene. Among them, naturalfibers from renewable resources, such as Miscanthus fiber, provideenvironmental benefits with respect to ultimate disposal as well as lowcost and high yield.

To enlarge the application field of polymer materials, super toughenedpolymer based materials (defined as notched impact strength >530 J/m[3]) have drawn scientific and industry attentions for decades sincetoughness is one of the most important properties in the realityapplication of these materials [4]. The impact resistance, a measure ofthe ability of a material to withstand the stress of a sudden loadwithout “failure” during its service lifetime, is a critical mechanicalproperty, because it relates to the safety, liability, and service lifeof the plastic product [5]. Therefore, toughening modification oftraditional brittle plastics such as polyvinyl chloride (PVC) [6],polystyrene (PS) [7], polyamide (PA) [8], polyethylene terephthalate(PET) [9] and polypropylene (PP) [10] has been extensively researchedand reported. However, with the increasing attention on the globalenvironmental issues and shortages of our finite petroleum resources,sustainable biodegradable polymers with superior properties should bepaid more attention in various fields such as packaging, automotive,household electricals and agriculture [11]. Amounts of novel biobasedand biodegradable polymers with different properties, such as Polylactide (PLA), poly(butylene succinate) (PBS), poly(butyleneadipate-co-terephthalate) (PBAT), and polycaprolactone (PCL) andpolyhydroxyalkanoate (PHA(s)), have been developed and modifiedextensively in recent years [2]. Nevertheless, inherent inferiorproperties of these polymers limit their applications for almost allstructural materials in market when used alone.

Melt blending different kinds of polymers, biodegradable ornon-biodegradable, has been proven to be an economic and effectivemethod in preparing balanced performance materials. Unfortunately, mostpolymer blends possess poor mechanical properties because of theimmiscibility of the polymer, so that simple physical blending does notusually yield satisfactory results. To improve the compatibility of theblends and increase the interfacial adhesion, a solution named “in-situextrusion reaction” that involves chemical reaction of the componentsduring melt blending is widely researched. In particular, reactiveblending makes it possible to improve impact strength to achieve‘super-toughened’ polymer materials which require strong interfacialadhesion between the matrix and dispersed phase.

Different types of reactions can be carried out in the reactive polymerprocessing, either from monomer or oligomers to high molecular weightpolymer [12], or more often, from polymer to modified polymer (grafting,functionalization or co-polymer formation), to shaped and structuredfinished products [13]. Because of the significant commercial value toindustry, most of the early work on reactive processing is to be foundin patent documents, and in a good deal of industrial secrecy [14].Different kinds of function groups, for e.g. maleic anhydride or acrylicacid, can attach on the saturated chain in the presence of afree-radical initiator through extrusion reactions. Another example ofchain modification reactive processing reactions is those that controlthe melt flow index by inducing controlled long chain branching or(light) cross-linking. However, as discussed previously, the majority ofnew blends of existing commodity or engineering polymers are practicallyimmiscible. Thus, commercial blends are made by reactively forming ablock copolymer at the interface during reactive polymer processingoperations. The early researched saturated chains are mainly HDPE, PP[15] and ethylene-propylene copolymer (EPR), etc. With the developing ofthe biodegradable polymers, more and more reaction extrusion researcheson these materials are carried out.

A number of patents and research publications have been filed thatdisclose the modification of bioplastics using reactive extrusion. U.S.Pat. No. 5,594,095 discloses the modification of polylactic acid withlinear organic peroxides such as2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and dicumyl peroxide, toimprove the melt strength of PLA. U.S. Pat. No. 8,334,348 B2 disclosesthe modification of biodegradable polymers using cyclic organicperoxide, resulting in (co)polymers with a high degree of branching butfree of gel formation. U.S. Pat. No. 8,231,954 B2 discloses a method ofproducing a thermoformable composite by crosslinking PHA and PLAtogether in the presence of an additive (peroxide) to produce PHA andPLA blend with high heat distortion index of up to about 160° C. U.S.Pat. No. 7,037,983 describes functional biopolymers with a vinyl monomerin the present of initiators such as free radical initiators. U.S. Pat.No. 7,393,590 discloses a coating or film formulation which by blendingpoly(lactic acid), and poly(epsilon caprolactone) together in thepresence of organic peroxide. Peroxide-induced crosslinked [16] orfunctional [17] biopolymers by reactive extrusion [18, 19]; peroxideinduced compatibility of biopolymer blends have been researched by manyinstitutes [20-23]. The above research shows that the peroxide can reactwith different kinds of biopolymers, such as PLA, PBS, PBAT, PHA,poly(3-hydroxy)butyrate (PHB) andpoly(3-hydroxybutyrate-hydroxyvalerate) (PHBV) et. al.

To fabricate super-toughened biopolymers with high impact strength,different kinds of polymer blends have been researched. U.S. Pat. No.5,252,642 depicts an environmentally degradable composition by blendingPLA with a blend-compatible elastomer that provides improved impactresistance. US 20150361258 discloses a formulation of super toughenedPLA-based blends showing non break impact with a thermoplasticelastomeric block copolymer and a functionalized polyolefin copolymer.US 20050137356 discloses a blends of 15 wt % to about 60 wt % flexiblebiodegradable and 85 wt % to 40 wt % rigid biodegradable polymers withimproved rheology and improved unnotched impact strength at least 20ft-lbs/in at 23° C. according to ASTM D256. U.S. Pat. No. 8,076,406relates to a composite having improved impact resistance by blending PLAwith polyamide and functionalized polyolefin. By blending 60 wt % PBSand 40 wt % PBAT together, Rajendran fabricated a biodegradableformulation showing non-break impact behavior [24]. As an importantelastomer, the ethylene based rubbers like ethylene methylacrylate-glycidyl methacrylate (EMA-GMA), poly(ethylene-glycidylmethacrylate) (EGMA) [25], poly (ether-b-amide) copolymer (PEBA), havebeen widely used in improving the toughness of biopolymers and performspositive results. Zhang's group have done systemic studies on thetoughening of PLA by EMA-GMA and EMAA-Zn, and they found that the typeof compatibilizer [26], blending temperature [27, 28], compositionratios, phase morphology and suitable interfacial adhesion [29]influence the final impact strength of the composites. Yury et. al. alsohave a research on the toughening PLA by EMA-GMA with Joncryl ascompatibilizer and found that the temperature influence the final impactstrength of the PLA blends [30]. Zhang et. al prepared a tougheningPLA/EMA-GMA/PEBA ternary blend by controlling the morphology [31]. Otherstudies on natural rubbers [32], epoxidized rubbers [33], thermoplasticvulcanizate (TPV) [34, 35] and vulcanized unsaturated aliphaticpolyester elastomer (UPE) [36] also have been investigated. So far, theelastomer is widely used as an impact modifier in the biodegradablepolymer. As far as we know, no results were reported on thesuper-toughened biodegradable composites (Notched Impact Strength >530J/m) based on the commercial biopolymer blends with high bio contents.

Reactive extrusion on PBS/PBAT binary or PLA/PBS/PBAT ternary blendsusing peroxide have not been reported. However, related reports onPLA/PBS, PLA/PBAT, PHBV/PBS, PHB/PBS or PLA/NR et al can be found. Inone report PLA/PBAT/Peroxide research, the peroxide (DCP) amounts wereused as 0.05, 0.1, 0.2, 0.5, 1 wt %. The notched Izod impact toughnessof these blends reaches a maximum (110 J/m) at the DCP content of 0.5 wt%. At 0.05 DCP, the impact strength is reported as ˜70 J/m, close to theblends without DCP (Ma et al. Polymer Degradation and Stability 102(2014) 145-151) and not a super toughened polymer. In another researchon the high impact strength of PBS/DCP (˜29 kJ/m2), the used DCP amountis 3 phr. While the reported impact strength is much lower (P. Ma et al.Macromol. Mater. Eng. 2013, 298, 910-918). In a recent research onPLA/NBR samples, the DCP dosage is as low as 0.045 wt %, but the impactstrength is reported as 18 kJ/m², i.e. not a super toughened polymer.The research all shows that small amount of peroxide is not enough forachieving high impact strength. And if high impact strength is required,high amounts of peroxide is always used. But the reported impactstrength is still much lower than the value for super-toughenedmaterials (˜530 J/m) which has been realized in the formulations of thepresent invention, suggesting a structural change in the composite notachieved or anticipated by prior studies.

Using small amounts of free radical initiator is advantageous becausethe gel content in the final products is closely related to the peroxidecontents. Gel content reduces the flowability of the blend. The lowflowability will limit the processing of plastics by the common methodssuch as extrusion and injection molding, increasing the manufacturingcost and energy consumption. The large use of peroxide in the reactiveextrusion will result in high gel contents (the reported gel content is80 wt % in the PBS+3 phr DCP (P. Ma et al. Macromol. Mater. Eng. 2013,298, 910-918)). However, the high gel contents are not good for thecommercial thermoplastic processing, like extrusion, injection or blownmolding. The reported crosslinked samples with large amounts of peroxideamount are usually prepared by compression molding which is not anefficient processing method.

The related research on the impact strength and gel contents of thebiodegradable/peroxide formulations are listed as follow table 1.

TABLE 1 The related results on impact strength and gel contents onbiodegradable/peroxide formulations Matrix Peroxide Impact Gel MaterialsUsed Strength Contents Reference Notes PBS DCP (3 phr) 29 kJ/m² 80 wt %P. Ma et al. Macromol. Mater. Eng. 2013, 298, 910-918 PLA/Natural DCP7.36 kJ/m2 Yun Huang et al. Charpy impact Rubbers J Polym Environ (2013)strength 21: 375-387 PLA80/PBAT20 DCP (0.5 phr) 110 J/m ¹ 6 wt %² 1. P.Ma et al. Polymer Degradation and Stability 102 (2014) 145-151 2.Francesca Signori et al. Macromol. Mater. Eng. 2015, 300, 153-160PLA75/PBAT25 Luperox Not Reported Not Reported Maria-Beatrice Coltelliet al. Improved tension (0.2) Polymer Degradation and strain from 20 to60% Stability 95 (2010) 332-341 PLA70/PBAT30 Tetrabutyl 9 kJ/m Notreported Shan Lin. et al. Materials and titanate Design 36 (2012)604-608 (0.2 phr) PLA90/PBS10 lysine 50-70 kJ/m² Not reported MasakiHarada, et al. Journal Charpy impact triisocyanate (Unnotched of AppliedPolymer Science. strength on (LTI) (0.5 phr) specimens) 106 (2017)1813-1820 unnotched specimens PLA/PBSA Triphenyl 16.4 kJ/m Vincent Ojijoet al. Charpy impact phosphite ACS Appl. Mater. Interfaces strength(TPP) (2 wt %) 2013, 5, 4266-4276 PBS DCP Not Reported ~75 wt % D. J.Kim et al. Improved tension (4 phr) Journal of Applied Polymer strainfrom 57 to 252% Science, Vol. 81, 1115-1124 (2001) PLA/PBAT/PC DCP 3kJ/m² Takeshi Kanzawa et al. Journal (0.3 phr) of Applied PolymerScience, Vol. 121, 2908-2918 (2001) PLLA 90/NBR 10 DCP ~18 kJ/m² Lu Liuet al. Ind. Eng. Chem. (0.045 wt %) Res. 2016, 55, 9907-9914 PHBV80/PBS20 DCP 55 kJ/m² ~27 wt % P. Ma et al. Macromol. Mater. (1 phr) Eng.2012, 297, 402-410

Besides the high impact toughness, heat deflection temperature (HDT) isalso important in the application of plastic materials because itdecides the upper limit temperature for utility of the products. Mostresearch on increasing the HDT is focused on increasing crystallinity ofthe materials or introducing fillers. For example, US 20160177086depicts a biodegradable polymer composition of PLA, aromatic aliphaticpolyester, cellulose fibers and nucleation agents, which show a highHDT. Both Rajendran and Zhang's studies showed that the addition ofMiscanthus fiber in the toughened biocomposites can increase the HDT ofthe materials [37, 38]. Therefore, different kinds of fillers are usedin the present examples to increase the HDT of the materials. On theother hand, by compounding binary blends with high contents PBS,super-toughened composites with high HDT were fabricated in the presentinvention, which is not reported in previous studies.

Avoiding the formation of gel (high MFI) of the high performance blendswith high impact toughness in the in-situ reactive extrusion isimportant and difficult to realize [39]. In this invention, a new methodis applied to achieve the target. In-situ degraded polymer chains (PHBVused here as an example) in the presence of peroxide is used here toincrease the MFI of the super-toughened binary or ternary blends, whichis not reported in previous studies.

The packaging industry has occupied 38% of the global plastic market forits wide application in our daily life [40]. The barrier properties arevery important for the packaging applications, and now prominentpetrol-based plastic used in the packaging industry include polyethylene(PE), polypropylene (PP), polyethylene terephthalate (PET) andpolystyrene (PS) for their good water or oxygen barrier properties [41].However, the barrier properties of biobased/biodegradable polymers aretypically low. Although the barriers can be improved via theintroduction of nanoclays [42], they still fare poorer than the abovepetrol-based plastics. Therefore, different kinds of fillers are used inthe present examples to increase the barrier properties of thematerials. Benefiting from the super-toughness and high melt strength ofthe binary/ternary matrix, toughen composites with high contents talcwith high barrier properties were fabricated in the present invention,which is not reported in previous studies.

US20180127554 describes using an anhydride grafted compatibilizer toimprove the properties of the biodegradable polymer blends via atwo-step processing.

Nano-blends are researched by many institutes and draw a wide interestof the researches because the nano structure blending can create supertough materials with high thermo-mechanical properties [43]. Normally,it is almost impossible to fabricate the nano-blends in a customaryblending. The most common approaches used to obtain nanostructure blendsare reactive blending [44], block copolymerization [45] and high shearprocessing [46]. In this invention, we y fabricated the nano-blends byusing a small amount of free radical initiator in an extruder, which wasnot reported anywhere else.

What is needed is a super-toughened fully biodegradable composition withbalanced stiffness—toughness—HDT properties. To the best of ourknowledge, no such composition has been reported in the previousresearches.

SUMMARY OF THE INVENTION

The present invention relates to a novel class of highly compatibilizedbiodegradable blends and biodegradable composites for industrialapplications, exhibiting high impact, high melt strength andstiffness-toughness balance, or a balance combination of high impact andHDT based polymer blends and their biocomposites. In one aspect, thecomposite formulation is designed to exhibit super-tough impact strengthto replace the traditional petrol-based polymers in applications likeinjection molding samples. In another aspect, the composite formulationis designed to exhibit high melt strength to replace the traditionalpetro-based polymers in some special applications like stretch shapingsamples. Also, the present invention relates to a novel method offabricating biodegradable nano-blends directly in a screw extruder.

The composites of the present invention utilize one-step in-situcompatibilization technology (reactive extrusion) to fabricate highlycompatibilized polymer blends of two or more biodegradable polymers. Theinvention also relates to the reactive extrusion to control the meltflow index (MFI) of varying novel formulations. Thus, accordingly thedesired formulations can be used either in injection molded, blowmolding, blown film or thermoforming type of molded products.

As such, in one embodiment, the present invention provides for anano-blend of two or more biopolymers comprising a nanostructured firstbiopolymer in a matrix of a second biopolymer.

In one embodiment of the nano-blend of the present invention, the firstbiopolymer is polybutyrate adipate terephthalate (PBAT), and the secondpolymer is polybutylene succinate (PBS).

In another embodiment of the nano-blend of the present invention, thefirst biopolymer is polybutylene succinate (PBS), and the second polymeris polybutyrate adipate terephthalate (PBAT).

In another embodiment of the nano-blend of the present invention, thenanostructured first polymer is 100 nm or less in diameter.

In another embodiment of the nano-blend of the present invention, thenano-blend further includes polylactic acid (PLA).

In another embodiment of the nano-blend of the present invention, thenano-blend comprises 60% wt. or less of PLA.

In another embodiment of the nano-blend of the present invention, thenano-blend further includes poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV).

In another embodiment of the nano-blend of the present invention, thenano-blend comprises 25% wt. or less of PHBV.

In another embodiment of the nano-blend of the present invention, thenano-blend comprises 25% wt. or less of PBAT.

In another embodiment of the nano-blend of the present invention, thenano-blend comprises 0.75 phr or less of a free radical initiator.

In another embodiment of the nano-blend of the present invention, thefree radical initiator is selected from dibenzoyl peroxide, benzoylperoxide, dicumyl peroxide, hydroperoxides and ketone peroxides.

In another embodiment of the nano-blend of the present invention, thenano-blend is a high melt flow biodegradable composite.

In another embodiment of the nano-blend of the present invention, thenano-blend is free of a functional monomer.

In another embodiment of the nano-blend of the present invention, thenano-blend is free of any gel content.

In one embodiment, the present application provides for a biodegradablecomposite. In one embodiment, the biodegradable composite of the presentinvention includes a nano-blend according to an embodiment of thepresent invention and one or more fillers.

In another embodiment of the biodegradable composite of the presentinvention, the composite comprises up to 60% by weight of the filler.

In another embodiment of the biodegradable composite of the presentinvention, the one or more fillers is selected from the groupconsisting: natural fibers from perennial grasses, cellulose andagricultural residues; inorganic mineral fillers; carbon fibers;by-products (biomass fillers) from coffee, tea and other agriculturalproducts; and a combination thereof.

In another embodiment of the biodegradable composite of the presentinvention, the perennial grasses include one or a combination of two ormore of miscanthus, switchgrass and bamboo.

In another embodiment of the biodegradable composite of the presentinvention, the inorganic fillers include one or a combination of two ormore of talc, clay and glass fiber.

In another embodiment of the biodegradable composite of the presentinvention, the biodegradable composite is in the form of a pellet, agranule, an extruded solid, an injection molding solid, a hard foam, asheet, a film, a dough or a melt.

In another embodiment of the biodegradable composite of the presentinvention, the biodegradable composite is compostable.

In another embodiment, the present invention provides for an article orproduct of manufacture including the biodegradable composite accordingto an embodiment of the present invention.

In one embodiment, the present invention provides for an in-situ methodof manufacturing a nano-blend of two or more biodegradable polymershaving a nanostructured first biodegradable polymer in a matrix of asecond biodegradable polymer, the in-situ method, in one embodiment,includes melting the first and the second biodegradable polymers in thepresence of an amount of a free radical initiator, thereby manufacturingthe nano-blend.

In one embodiment, the present invention provides for an in-situ methodof manufacturing a nano-blend of two or more biodegradable polymershaving a nanostructured first biodegradable polymer in a matrix of asecond biodegradable polymer, the in-situ method, in one embodiment,consists essentially of, or consists of, melting the first and thesecond biodegradable polymers in the presence of an amount of a freeradical initiator, thereby manufacturing the nano-blend.

In one embodiment of the in-situ method of the present invention theamount free radical initiator is 0.75 phr or less.

In another embodiment of the in-situ method of the present invention thetwo or more biodegradable polymers are selected from: Poly lactide(PLA), poly(butylene succinate) (PBS), poly(butyleneadipate-co-terephthalate) (PBAT), and polycaprolactone (PCL) andpolyhydroxyalkanoate (PHA(s)), poly(3-hydroxy)butyrate (PHB) andpoly(3-hydroxybutyrate-hydroxyvalerate) (PHBV).

In another embodiment of the in-situ method of the present invention thetwo or more biodegradable polymers are polybutylene succinate (PBS) andpolybutyrate adipate terephthalate (PBAT).

In another embodiment of the in-situ method of the present invention thefree radical initiator is dibenzoyl peroxide, benzoyl peroxide, dicumylperoxide, hydroperoxides, ketone peroxides or a combination thereof.

In one embodiment, the present invention provides for a method ofmanufacturing a biodegradable composite, the method, in one embodiment,includes: (a) manufacturing a nano-blend using the in situ methodaccording to any embodiment of the present invention; and (b) adding afiller to the nano-blend, thereby manufacturing the biodegradablecomposite.

In one embodiment of the method of manufacturing a biodegradablecomposite of the present invention, the filler is selected from one or acombination of two or more of the following: natural fibers fromperennial grasses, cellulose and agricultural residues; inorganicmineral fillers from talc or clay; glass fibers or carbon fibersfillers; by-products (biomass fillers) from coffee, tea and otheragricultural products.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures illustrate various aspects and preferred andalternative embodiments of the present invention.

FIG. 1 Three-roll calendaring sheet made of a binary composite withfillers of the present invention.

FIG. 2 Blown film of the compatibilized binary blends with talcaccording to one aspect of the present invention.

FIG. 3 Impact samples from injection molded part made of a ternarymatrix with 20 wt % fillers (Miscanthus fibers) according to one aspectof the present invention.

FIG. 4 Injection molded part made of a binary matrix with a secondbiodegradable polymer (PHBV) according to one aspect of the presentinvention.

FIG. 5 Thermoformed products or articles made of a compatibilized binarycomposite and the composites with 20 wt % fillers (Miscanthus fibers andtalc) according to aspects of the present invention.

FIGS. 6A-6C: Electron microscope image of different blends. FIG. 6A:nano dispersion of PBAT in the PBS of PBS95-PBAT5-Luperox 0.02 binaryblend according to one aspect of the present; FIG. 6B dispersion of PBATin the PBS of the binary blend of PBS95-PBAT5 with no free radicalinitiator, showing no nano-blend dispersion; FIG. 6C dispersion of PBATin the PLA/PBS/PBAT/Luperox 0.75, showing no nano-dispersion.

DESCRIPTION OF THE INVENTION Definitions

The following definitions, unless otherwise stated, apply to all aspectsand embodiments of the present application. Unless defined otherwise,all technical and scientific terms used herein have the same meaning ascommonly understood by one of ordinary skill in the art to which thisinvention belongs. Also, unless indicated otherwise, except within theclaims, the use of “or” includes “and” and vice versa. Non-limitingterms are not to be construed as limiting unless expressly stated or thecontext clearly indicates otherwise (for example “including”, “having”and “comprising” typically indicate “include without limitation”).“Consisting essentially of” shall mean that the blends, composites,articles and methods of the present invention include the recitedelements and exclude other elements of essential significance to thecombination for the stated purpose. Thus, a blend, composite, article ormethod consisting essentially of the elements as defined herein wouldnot exclude other materials or steps that do not materially affect thebasic and novel characteristic(s) of the claimed invention. “Consistingof” shall mean that the blends, composites, articles and methods of thepresent invention include the recited elements and exclude anything morethan a trivial or inconsequential element or step. Embodiments definedby each of these transitional terms are within the scope of thisdisclosure.

Singular forms included in the claims such as “a”, “an” and “the”include the plural reference unless expressly stated otherwise. Allrelevant reference, including patents, patent applications, governmentpublications, government regulations, and academic literature arehereinafter detailed and incorporated by reference in their entireties.

The term “plurality,” as used herein, is defined as two or more thantwo. The term “another,” as used herein, is defined as at least a secondor more. The phrase “at least one of . . . and . . . ” as used hereinrefers to and encompasses any and all possible combinations of one ormore of the associated listed items. As an example, the phrase “at leastone of A, B and C” includes A only, B only, C only, or any combinationthereof (e.g. AB, AC, BC or ABC). The term “substantially” includesexactly the term it modifies and slight variations therefrom.

The term “about” modifying any amount refers to the variation in thatamount encountered in real world conditions of producing materials suchas polymers or composite materials, e.g., in the lab, pilot plant, orproduction facility. For example, an amount of an ingredient employed ina mixture when modified by about includes the variation and degree ofcare typically employed in measuring in a plant or lab and the variationinherent in the analytical method. Whether or not modified by about, theamounts include equivalents to those amounts. Any quantity stated hereinand modified by “about” can also be employed in the present invention asthe amount not modified by about

The prefix “bio-” is used in this document to designate a material thathas been derived from a renewable resource.

The term “renewable resource” refers to a resource that is produced by anatural process at a rate comparable to its rate of consumption (e.g.,within a 100 year time frame). The resource can be replenishednaturally, or via agricultural techniques.

The term “biobased content” refers to the percent by weight of amaterial that is composed of biological products or renewableagricultural materials or forestry materials or an intermediatefeedstock.

The term “biodegradable” refers to a composite or product capable ofbeing broken down (e.g. metabolized and/or hydrolyzed) by the action ofnaturally occurring microorganisms, such as fungi and bacteria.

The term “compostable” refers to a composite or product that satisfiesrequirement, set by ASTM D6400, for aerobic composting in municipal andindustrial facilities. In a brief note, a compostable materialfulfilling ASTM D6400 requirements is substantially broken down incompost at a rate that is consistent with known compostable materials(e.g. cellulose), disintegrates into small pieces and leaves no toxicresidue.

The term “hybrid composite/biocomposites” refers to thecomposite/biocomposites including any combination of two or more typesof different biomass.

The term “highly compatibilized composites” refers to a composite inwhich no phase separation can be observed in micro-scale by microtechnique such as scan electrical microscopy (SEM) or optical microscopy(OM) technology. In some case nano-scale dispersed phase can be found inthe highly compatibilized composites.

The term “super-tough” refers to a composite with notched impactstrength higher than 530 J/m in standard ASTM D256 testing.

The term “miscibility” refers to thermodynamically miscible; eachmixture is characterized by a single thermal transition as well as asingle amorphous phase.

The term “nano-blends” or “nano-structure” refers to a dispersedpolymeric phase in a blend system having domains or dispersed particlesbelow 100 nm in diameter.

Reference herein to the terms “homogeneous blend” or “homogeneousnano-blend” are to be understood to refer to blends having a uniformmixture wherein the nano-structures or domains in the blend are evenlydistributed throughout the whole blend. FIG. 6A is a non-limitingexample illustrating a homogeneous blend or nano-blend having a uniformnano dispersion of PBAT in the PBS of a PBS95-PBAT5-Luperox 0.02 binaryblend according to one aspect of the present.

The term “melt strength” refers to the resistance of the polymer melt tostretching, which influence drawdown and sag from the die to the rollsin polymer processing.

The term “MFI” refers to the melt flow index of the polymer blends orcomposites, which influence the flowability of the materials in polymerprocessing.

The term “barrier” refers to the properties seal the contents (Oxygen,nitrogen, carbon dioxide, water vapor, and other gases in the air) fromoutside factors and protect the products (food, beverage, et al.) toprevent degradation in quality, which is important for the packagingmaterials.

The term “stretch shaping” refers to the stretch or extensionalflow-based shaping operations take place downstream from the die, suchas melt fiber spinning, tubular film blowing, blow molding andthermoforming.

The term “free radical initiator” refers to substances that can produceradical species under mild conditions and promote radical reactions.Non-limiting examples of “free radical initiators” that can be used inthe present invention include: dibenzoyl peroxide, benzoyl peroxide anddicumyl peroxide, including but not limited to:2,5-dimethyl-2,5-di(t-butylperoxy) 3-hexyne;2,5-dimethyl-2,5-di(t-butylperoxy) hexane;2,5-dimethyl-2,5-di(t-amylperoxy) hexane;4-(t-butylperoxy)-4-methyl-2-pentanol;Bis(t˜butylperoxyisopropyl)benzene; Dicumyl peroxide; Ethyl3,3-bis(t-butylperoxy) butyrate; Ethyl 3,3-bis(t-amylperoxy) butyrate;and, Dibenzoyl peroxide.

The term “gel” refers to crosslinked blends or composites which cannotbe dissolved in an organic solvent.

The term “wt. %” refers to the weight percent of a component in thecomposite formulation with respect to the weight of the whole compositeformulation.

The term “about” modifying any amount refers to the variation in thatamount encountered in real world conditions of producing materials suchas polymers or composite materials, e.g., in the lab, pilot plant,production facility. Whether or not modified by about, the amountsinclude equivalents to those amounts. Any quantity stated herein andmodified by “about” can also be employed in the present invention as theamount not modified by about.

Overview

Henceforth, this document provides detailed description of theembodiments of the present invention. The present invention providesbinary blends and ternary blends having super toughened properties usingrelatively small amounts of peroxide. The binary and ternary blends ofthe present invention provide the opportunity to add fillers thatcontribute to lower the costs of the composites, increase the MFI andHDT of the composite without much sacrificing the impact strength andwater/oxygen barrier properties.

For the first time, gel free samples with high performance (like highimpact strength, high melt strength) were achieved in the presentinvention via dispersing one phase into nano-scale in the presence ofsmall amount of free radical initiators.

Different from US20180127554, which uses an anhydride graftedcompatibilizer to improve the properties of the biodegradable polymerblends via a two-step processing, the present invention does not needany compatibilizer. A free radical initiator is added into the polymerblends directly via one-step process (i.e. a one step in situ method),to improve the compatibility of the blends via in-situ free radicalreactions resulting in a nano-blend. The active reactions between thefree radical initiator and different kinds of biodegradable polymersendow the binary, ternary or quaternary blends high compatibility andsuper toughness. And for binary blends of PBS and PBAT, for the firsttime, nano-structures can be found in the blends of the presentinvention.

In one embodiment, the present invention provides a composition, methodor manufacture of biocomposites which may be based on the in-situreactive extrusion via one-step (single step) process in the presence offree radical initiators, with addition of fillers based on perennialgrasses (including but not limited to miscanthus fibers), and/oragricultural residues (including but not limited agricultural straws)and/or mineral fillers (including but not limited to talc), and/orfibers (including but not limited to glass fibers), or with addition ofa second biodegradable polymers (including but not limited to PBS, PLA,PHBV), and/or biobased plasticizers (including but not limited to soyoil, soy wax), and/or biodegradable oligomer (including but not limitedto low polymerization degree poly (Lactide acid) (low DP poly (lactideacid)) or low molecular weight polyethylene glycol (PEG)). Abiodegradable matrix composed of biodegradable thermoplastics which maybe reinforced or not with the above fillers and which may be produced byreactive extrusion suitable for general purpose application such as foodcontainers and the like. Conventional extrusion, injection moldingand/or thermoforming, normally used in the synthetic plastic industries,may also be used in the method of processing.

The biocomposites of the present invention may exhibit propertiestypical of plastic materials, and/or properties advantageous compared toaggregates including plastic and, for example, wood or cellulosicmaterials.

The biocomposites of the present invention may be formed into usefularticles using any of a variety of conventional methods for formingitems from plastic. The present biocomposites may take any of a varietyof forms.

Biocomposites and Method of Manufacturing

The present invention relates to a new and non-obvious materialformulations based on biodegradable polymeric matrix in the presence offree radical initiators. This invention could enable tailor highlycompatibilized blends and composites by using an amount of a freeradical initiator that does not result in the formation of gel or thatresults in the formation of small amounts of gel (5.4 gel content orless). The free radical initiator could be used in an amount of 0.75 phror any amount under 0.75 phr, such as 0.5 phr or less, 0.3 phr or less,0.05 phr or less. In one particular embodiment of the present invention,a nano-blend is fabricated with a small amount of peroxide as low as0.02 phr. Also, the present invention is about development andproduction methods of new biocomposites based the mentioned polymericmatrix with different kinds of fillers (including but not limited tomiscanthus fibers, talc, clay, glass fibers). Also, the presentinvention is about development and production methods of newbiodegradable blends based the above mentioned polymeric matrix withdifferent kinds of second biopolymers (including but not limited to PLA,PHBV and PBS). The present invention has distinguished points comparedto the prior art in both aspects of material properties and productionmethod.

i. Biodegradability: The biocomposites of the present invention may beformulated in such a way that the final manufactured product would haveend of life biodegradability (compostability) characteristic. To developsuch biocomposites, the proposed formulation may include a polymericmatrix from biodegradable plastics, including but not limited to Polylactide (PLA), poly(butylene succinate) (PBS), poly(butyleneadipate-co-terephthalate) (PBAT), and polycaprolactone (PCL) andpolyhydroxyalkanoate (PHA(s)), poly(3-hydroxy)butyrate (PHB) andpoly(3-hydroxybutyrate-hydroxyvalerate) (PHBV).

ii. Renewability: The polymer blends used in the present invention maybe produced, at least in part, from renewable resources. Thus,considering the renewability of the filler also the final formulationcan be produced from renewable materials higher than 50% by weight ofthe whole composites.

iii. Free radical reaction: A free-radical reaction is any chemicalreaction involving free radicals. In organic reactions, the radicals areoften generated from radical initiators such as peroxides.

iv. Binary, ternary or quaternary blends with tailored properties: thedeveloped formulation of the present invention includes a polymericmatrix blend which may include a combination of any two or morebiodegradable polyesters including but not limited to Poly lactide(PLA), poly(butylene succinate) (PBS), poly(butyleneadipate-co-terephthalate) (PBAT), and polycaprolactone (PCL) andpolyhydroxyalkanoate (PHA(s)), poly(3-hydroxy)butyrate (PHB) andpoly(3-hydroxybutyrate-hydroxyvalerate) (PHBV). Blending may benefitfrom the specific merits of each moiety in order to balance differentproperties. To create such a balance, the following aspects may beconsidered simultaneously: rigidity/modulus (PHAs, PHBV and PLA),strength (PLA and PBS), impact strength (PBAT and PCL), elongation (PBS,PBAT and PCL), heat deflection temperature (PHAs, PBS, PHB, PHBV),renewable resource based (PHAs, PLA and PBS), good flowability (PHB,PHBV) and low cost (PLA).

v. Highly compatibilized composites. Based on the targeted applicationwith specific requirements, in the present invention, a convenientmethod of producing highly compatibilized composites has been utilized.In the presence of free radical initiators, a binary or ternary blend ofbiodegradable polyesters such as PLA, PBS, and PBAT are highlycompatibilized without gel formation via in-situ reactive extrusion withachieving super high impact. The developing of such compatibilizationtechnology provides opportunities in tailoring the properties (such asmelt flow index, rheological and impact strength) of the composites madetherefor.

vi. Free of gel formation. In the present invention, super toughenedbiodegradable polymer blends without any gel content have been preparedby one-step extrusion in the presence of small amount of free radicalinitiator.

vii. Nano-blends: As illustrated in FIG. 6A, the blends of the presentinvention are characterized by being nano-blends in which the size ofone polymeric phase is below 100 nm.

viii. High barrier polymeric composites: In the present invention, supertoughened biodegradable composites with high filler loadings has beenprepared by one-step extrusion. The target is to achieve high barrierproperties for packaging applications. The developing of suchcompatibilization technology provides opportunities in making highbarrier composites with good mechanical properties (toughness,stiffness) made therefor.

In order to aid in the understanding and preparation of the presentinvention, the following illustrative, non-limiting examples areprovided.

Examples Materials

Table 2 includes a list of materials or ingredients that can be used toproduce the novel formulations of the present invention.

The polymeric matrix of the biocomposites of the present inventionincludes renewable resource derived polymers such as PLA or the alike,biodegradable polymers such as PBAT. It may include other biodegradablepolymers such as PBS, PHAs, PCL.

The free radical initiator of the present invention includes differentperoxides, dibenzoyl peroxide, benzoyl peroxide and dicumyl peroxide orthe alike.

TABLE 2 Materials that can be used to produce the novel formulationsproposed in this invention Material Examples Role Biodegradable PLA,PBS, PBAT, PCL, PHAs, Matrix Polymers PHBV and alike PerennialMiscanthus, Switchgrass, bamboo Filler/Reinforcing Grasses and the likeagent Inorganic Talc, Clay, Calcium carbonate, Filler/Reinforcingfillers glass fibers and the like agent By-products Coffee chaff, spenttea leaves, Filler/Reinforcing of agricultural grape pomace, oat hullagent products and the like Peroxide-based dibenzoyl peroxide, benzoylFree radical chemicals peroxide, dicumyl peroxide, initiatorhydroperoxides, Ketone peroxides and the like

The poly (lactic acid) or polylactide, both indicated as PLA in thisapplication, can be produced by condensation polymerization of lacticacid or ring opening polymerization of lactide, respectively. Usually,the lactide can be synthesized by a chemical method using a fossilresource such as petroleum or natural gas. However, lactic acid producedby fermentation of sugars from starch, molasses or the like may bepreferred and used in the present invention. The PLA can be high or lowmelt flow index with high tension modulus (about 4.5 GPa), tensionstrength (about 65 MPa), low elongation at break (about 3%) and lowimpact strength (about 25 J/m).

The poly (butylene adipate-co-terephthalate) (PBAT) is a petroleum basedaliphatic-aromatic biodegradable copolymer randomly polymerized from thepolycondensation of 1,4-butanediol. It has high elongation at break of˜700%, high impact strength showing non-break and low tension modulusand strength.

The poly (butylene succinate) (PBS), synthesized by condensationpolymerization of succinic acid and butanediol, is a biodegradablepolymer. The source of production of PBS can be synthesized from eitherfossil resource or biological resources, the latter usually labeled as“BIOPBS”. PBS has high elongation at break of 350%, tension modulus of˜750 MPa, high HDT values of ˜90° C. but low impact strength of ˜30 J/m.

Polyhydroxyalkanoates or PHAs are linear polyesters produced in natureby bacterial fermentation of sugar or lipids. They are produced by thebacteria and store carbon and energy. PHAs are a very versatile familyin which different members possess different properties, stiff or tough,crystalline or amorphous. More important is that all members of the PHAfamily are biodegradable. Both PHB and PHBV are members of the PHAsfamily, the former is homopolymer while the latter is copolymer.

Perennial grasses are typical lignocellulosic biomass and promisingnon-food crop with high yield, low cost, soil remediation potential andcarbon dioxide balance in environment. The advantage of using perennialgrasses in this application is their good reinforcement of modulusproperties and increased HDT, as well as the strong potential for areliable supply chain.

The free radical initiators consist of organic peroxide group withdifferent chemical structures. The peroxide may be in the form ofperoxide, hydroperoxides, peroxy esters and ketone peroxide, includingbut not limited to 2,5-dimethyl-2,5-di(t-butylperoxy) 3-hexyne;2,5-dimethyl-2,5-di(t-butylperoxy) hexane;2,5-dimethyl-2,5-di(t-amylperoxy) hexane;4-(t-butylperoxy)-4-methyl-2-pentanol;Bis(t˜butylperoxyisopropyl)benzene; Dicumyl peroxide; Ethyl3,3-bis(t-butylperoxy) butyrate; Ethyl 3,3-bis(t-amylperoxy) butyrate;and, Dibenzoyl peroxide.

Methods

The compositions produced by the following method can be used forgeneral purposes including but not limited to plastic containers as wellas degradable and disposable items such as flower pots, food and coffeetrays, horticultural trays, storage bins, disposable consumer products,food packaging, single use containers, parts, tool boxes, bathroomaccessories, dust pans, spray guns and the like.

Production of In-Situ Reaction Extruded Composites Based onBinary/Ternary Blends

Prior to melt processing, all polyesters were dried in the oven at 80°C. for at least 12 hr. The methods related to an in-situ reactiveextrusion are performed in presence of a free radical initiator. Thefree radical initiator used in the following example is2,5-Bis(tert-butylperoxy)-2,5-dimethylhexane, also known as2,5-Bis(tert-butylperoxy)-2,5-dimethylhexane or Luperox 101. Other freeradical initiator, including linear peroxide, cyclic organic peroxide,benzoyl peroxide, dicumyl peroxide or the like, can also be used in thisapplication.

The in-situ reaction of the binary/ternary biopolymer blends in thepresence of free radical initiator can be performed on Haake mixers orthe like, micro-compounders with integrated extrusion and injectionmolding systems (i.e. DSM micro injection molding), or in any extrudeand injection molding systems normally used to process thermoplastics.When an extruder is used, which is a preferred method of processing,strands are produced in a continues process which can be pelletized andfurther processed by other process method such as injection molding,three roll calendaring (see FIG. 1), film blowing (FIG. 2) or the like.The use of twin-screw extruder systems is determinant in the productionof inexpensive materials and it is a rapid way to obtain masscommercially valuable polymers.

The twin-screw extruder in the presented work is a corotating twin screwextruder (Leistritz Micro-27, Germany) with a screw diameter of 27 mmand an L/D ratio of 48. This extruder may present 10 heating zones orless. It required degassing pump when the reactive extrusion isperformed. It may require two feed barrel zones by which indistinctlythe polymers and the fillers/reinforcing agents are fed. The main feedspeed and the side stuffer feed speed should be matched to ensure thecomposition ratio between the polymer and fillers.

The temperatures of processing may vary from 120 to 250° C., or anyrange between 120 and 250° C. The processing conditions are listed inTable 3.

TABLE 3 Extrusion parameters and additive concentrations used forfabrication of in-situ compatibilized composites Parameters ConditionsProcessing temperature 120 to 250° C. Screw Speed 20-150 rpm Residencetime 0.2-10 min Filler/Reinforcing Agent 0.01-60 wt % Free RadicalInitiator 0.0001-15 phr

The in-situ reaction is prepared through (1) pre-mixing one or morebiodegradable polymers and a free radical initiator; (2) melting step(1) thereby manufacturing the highly compatibilized biodegradablematrix. In the present application, the continuous processing wasconducted in a twin screw extruder manufactured by Leistritz, Germany.The melt mixing process can be performed in other process equipmentincluding, but not limited, Hakke mixer, single screw extrude ormicro-compounders like DSM using the parameter in Table 3.

Unreacted or excess free radical initiator and other small molecularby-product can be purified by the following method: 1)Devolatilization—applying vacuum to vent off volatile during extrusionprocess; 2) drying the synthesized matrix under vacuum at 95° C. untilthe desired level of un reacted free radical initiator in the matrix isreached.

Sample preparation and Characterization

The extruder pellets can be shaped into desired geometry by anyconventional polymer processing technique including but not limited toinjection molding (see FIGS. 3 and 4), compression molding, three-rollcalendaring (see FIG. 1), film blowing (see FIG. 2) and vacuumthermoforming (see FIG. 5).

In the examples provided in this application, tensile, flexural andimpact test bars are manufactured from the pellets by using amicro-injection molding instrument of DSM Explore, Netherlands. Theextruded pellets were melted in a micro-compounder followed by immediateinjection in a micro-injector both manufactured by DSM explore, theNetherlands, in the melting temperature range from 120-250° C., moldingtemperature from 30-80° C.

Specimens to measure the tensile and flexural properties as well asimpact strength are produced and tested according to the followingstandards ASTM: D638 (standard test method for tensile properties ofplastics), D790 (standard test method for flexure properties ofreinforced and unreinforced plastics and electrical insulatingmaterials), D256 (notched izod; standard test method for determining theIzod pendulum impact resistance of plastics). The heat deflectiontemperature is measured using a dynamic mechanical analyzer (DMA) fromTA, USA with sample bars of 3.3×2.7×60 mm³ in a 3-point bending mode,temperature ramp rate of 2° C./min and loading force of 0.455 MPaaccording to the ASTM D648. The gel contents of the blends arecalculated by the dissolve-extraction method according to ASTM D2765.The polymer is sealed in stainless steel wire mesh and dissolved inchloroform for 24 h. After extraction, the undissolved parts aretransferred into a vacuum oven at 40° C. for 3 days to remove thechloroform. The residue of the insoluble polymer is weighted andreported as wt 0 gel content. The oxygen and water barrier properties ofthe plastic samples is measured using a Mocon permeation instrument(OX-Tran Model 2/21L and Permatran-W Model 2/21L, Ameter Mocon, Ltd,USA) according to the ASTM D1434 and ASTM D697.

Results In-Situ Compatibilized Composites Based onBinary/Ternary/Quaternary Blends Composites Based on a Binary BlendMatrix

The effect of the composition ratio and compatibilization via theone-step reactive extrusion on the properties of the binary compositesis presented in Table 4.

TABLE 4 PBS/PBAT binary blends and their composites Samples MatrixLuperox Tension Tension Elongation Elongation Flexure Flexure ImpactComposition contents Modulus Strength at Yield at break Modulus strengthstrength HDT (wt %) (phr) (MPa) (MPa) (%) (%) (MPa) (MPa) (J/m) (° C.)PLA 100 0 4510 ± 354.9 74.9 ± 8.65 —  2.72 ± 0.35 3114 ± 22   106 ± 0.8432.862 ± 1.301 55 PBS 100  613 ± 23.18 48.7 ± 2.36 17.91 ± 0.38 267.3 ±24.5  351 ± 2.8 16.2 ± 0.1    79 ± 28.834 88 PBAT 100 70 ± 7.5 27.6 ±1.97 559.5 ± 56.0 574.4 ± 53.3 53 ± 2 2.54 ± 0.1 Non-break 45 PBS 80 0457 47.4 14.5 372.96 449 20.10 243.725 83.69 PBAT 20 (33.5) (4.43)(0.43) (12.45) (1.66) (0.07) (163.079) 0.02 460 47.3 27.17 146.07 37916.36 689.233 82.5 (12.64) (0.75) (0.17) (6.82) (6.8) (0.28) (47.989)COMPOSITES (Filler Effect) PBS80/PBAT20-L0.02/ 1314 31.7 9.35 23.46 101633.46 168.704 96.61 20 wt % Miscanthus Fiber (64.77) (1.07) (0.14)(2.86) (87.9) (0.83) (4.9) PBS80/PBAT20-L0.02/ 1316 42.5 18.14 33.171152 35.16 160.643 97.07 20 wt % Talc (64.54) (0.21) (0.17) (1.38)(34.1) (0.71) (10.04)

TABLE 5 PBS/PBAT binary blends with Different PBAT contents MFI ModulusTension Elongation Elongation Flexure Flexure Impact (g/10 min)(Young's) Strength at Yield at break Modulus Strength strength HDT 210°C., Samples (MPa) break(MPa) (%) (%) (MPa) (MPa) (J/m) (° C.) 7.16 kgPBS 95/PBAT5 705 52.4 21.15 137.68 724 29.35 504.92 81.31 0.35 Luperox0.02 (41.02) (1.07) (0.34) (12.52) (10.65) (0.24) (59.88) PBS 90/PBAT10/593 53.9 21.90 139.71 639 26.0 580.403 82.95 0.23 Luperox 0.02 (19.79)(1.23) (0.07) (10.09) (10.07) (0.41) (156.2) PBS 85/PBAT15/ 520 48.221.75 168.16 527 21.9 718.483 81.48 0.20 Luperox 0.02 (48.97) (1.55)(0.33) (13.16) (49.33) (1.39) (55.141) PBS 80/PBAT20/ 460 47.3 27.17146.07 379 16.36 689.233 82.5 0.16 Luperox 0.02 (12.64) (0.75) (0.17)(6.82) (6.8) (0.28) (47.989)

The binary blends presented in these examples are based on a combinationof a relatively tough polymer (PBS in this case) and another toughpolymer with high impact strength (PBAT in this case) biodegradablepolymers. The matrix can also be selected from other biodegradablepolymers but not limited to PHAs, PCL, Polyglycolide (PGA), et al. Eachbiodegradable polymer may vary in the range of 0.01 to 99 wt %0 byweight of the whole composites, more preferably in the range of 0.01 to20 wt % of PBAT to remain the high bio-contents of the composites.

As shown in tables 4 and 5, the increase of the tough polymer portion inthe matrix can increase the impact strength of the materials remaininghigh HDT values. The high impact strength of PBS/PBAT/Luperox blendswith low amount of PBAT is ascribed to the formation of nano-structurein the high compatibility system, as shown in FIG. 6A. In PBS/PBAT blendwith 0.02 phr of peroxide we could achieve an increase of % elongationat yield by almost two times from 14.5 to 27.5%. By using such smallamount of peroxide, the gel contents of the blends can be controlled to0. More notably such gel free compatibilized blend in presence of 20%Miscanthus fiber/Talc made most innovative biodegradable composites.With such 20% filler contents we still found % elongation yield of 9%and 18% which are not usual in composite materials. Again, such inventedbiodegradable formulations have tensile modulus of more than 1.3 GPa andHDT values nearer to 100° C. Such biodegradable formulations would findvarying industrial uses. However, in such formulation, the free radicalinitiator can be selected from the ones listed in Table 2, in the rangeof 0.0001 phr-15 phr by weight of the whole composites. And thefiller/reinforcing agent can also be selected, but not limited to, fromthe ones listed in Table 2, in the range of 0.01 to 60 wt %.

Composites Based on a Ternary/Quaternary Blend Matrix

The effect of the composition ratio and compatibilization via theone-step reactive extrusion on the properties of the ternary compositesis presented in Table 6.

TABLE 6 PLA/PBS/PBAT ternary blends and their composites Samples MatrixLuperox Tension Tension Elongation Elongation Flexure Flexure ImpactComposition contents Modulus Strength at Yield at break Modulus strengthstrength HDT (wt %) (phr) (MPa) (MPa) (%) (%) (MPa) (MPa) (J/m) (° C.)PLA 100 0 4510 ± 354.9  74.9 ± 8.65 —  2.72 ± 0.35 3114 ± 22 106 ± 0.8432.862 ± 1.301 55 PBS 100 613 ± 23.18 48.7 ± 2.36 17.91 ± 0.38  267.3 ±24.5  351 ± 2.8 16.2 ± 0.1     79 ± 28.834 88 PBAT 100 70 ± 7.5  27.6 ±1.97 559.5 ± 56.0  574.4 ± 53.3  53 ± 2 2.54 ± 0.1  Non-break 45 PLA 800 2799 ± 78.52  30.7 ± 2.74 2.99 ± 0.17 50.89 ± 22.7 2722 ± 20 83 ± 5.245.297 ± 3.687 50.6 PBS 10 0.3 2533 ± 268.74 31.8 ± 1.08 3.08 ± 0.1294.69 ± 7.48 2511 ± 11 76 ± 1.3 37.223 ± 2.61  48.9 PBAT 10 0.5 2958 ±371.48 31.2 ± 1.87 2.93 ± 0.1  61.32 ± 22.6 2340 ± 80 72 ± 1.7 35.074 ±4.203 49.8 0.75 3240 ± 333   30.9 ± 1.15  2.8 ± 0.13 43.24 ± 27.3 2418 ±96 73 ± 1.7 34.235 ± 2.723 49.2 PLA 60 0 2385 ± 607.28 32.5 ± 3.26 3.15± 0.38 99.63 ± 9.5  2001 ± 44 63 ± 1.1  78.441 ± 13.809 52.6 PBS 20 0.022028 ± 29.52  43.4 ± 2.6  3.18 ± 0.88 155.8 ± 33.2  1901 ± 147 56.2 ±1.3  524.402 ± 72.856 52.6 PBAT 20 0.3 1965 ± 269.84 31.4 ± 0.73 3.35 ±0.15 103.47 ± 7.6  1751 ± 10 56 ± 0.7 728.709 ± 22.355 48.5 0.5 1710 ±160.47 30.7 ± 1.52 3.77 ± 0.12 87.63 ± 3.55 1737 ± 13 55 ± 0.7 915.932 ±49.96  48.7 0.75 2750 ± 280.02 35.9 ± 1.67 3.96 ± 0.10 56.97 ± 16.8 1613± 29 52 ± 1.9 940.886 ± 32.261 48.1 PLA 40 0 1417 ± 180.19 33.5 ± 1.956.78 ± 1.37 167.7 ± 12.5 1184 ± 49 44 ± 1.7 111.507 ± 19.686 49.4 PBS 400.02 1501 ± 70.3  42.7 ± 1.65  6.2 ± 0.15 168.2 ± 6.19  1358 ± 9.1  48 ±0.35 996.55 ± 26.06 50.7 PBAT 20 0.3 1309 ± 91.75  33.9 ± 1.1  14.24 ±1.15  105.7 ± 6.01 1218 ± 10 42 ± 0.2  1003.1 ± 60.532 48.5 0.5 1269 ±100.07 34.4 ± 1.9  16.14 ± 1.65   85.5 ± 16.44 1195 ± 23 41 ± 1  1014.18± 32.873 49.1 0.75 1289 ± 80.4  38.1 ± 0.46 47.34 ± 8.36   48.3 ± 6.181216 ± 20 40 ± 1  976.607 ± 52.405 51.3 COMPOSITES (Filler Effect)P-S40T20-L0.02/20 wt % 4385 ± 369   29.5 ± 5.7  3.05 ± 0.09 8.48 ± 2.5 3336 ± 153 71 ± 1.9 140.56 ± 11.41 78.0 Glass Fiber P-S40T20-L0.02/20wt % 3732 ± 377   33.8 ± 0.42 3.27 ± 0.55  7.84 ± 1.31 2099 ± 31 51.3 ±1.5  114.85 ± 22.23 56.4 Miscanthus Fiber P-S40T20-L0.02/20 wt % 2762 ±97    37.1 ± 0.49 5.25 ± 0.22 93.25 ± 34.3  2692 ± 213 56.3 ± 2.8 171.17 ± 30.43 54.5 Talc

The ternary blends presented in these examples are based on acombination of a relatively rigid (PLA in this case) and two relativelytough (PBS and PBAT in this case) biodegradable polymers. The matrix canalso be selected from other biodegradable polymers but not limited toPHBV, PHAs, PCL, Polyglycolide (PGA). Each biodegradable polymer mayvary in the range of 0.01 to 99 wt % by weight of the whole composites,more preferably in the range of 0.01 to 20 wt % of PBAT to remain thehigh bio-contents of the composites.

As shown in table 6, the increase of the tough polymer portion in thematrix can improve the elongation as well as the impact strength of thematerials with balanced stiffness (modulus higher than 1.2 GPa). In aspecific PLA/PBS/PBAT blends with 0.02 phr Luperox peroxide, we find thesamples shown high stiffness (˜2.0 GPa), high elongation at break(˜155%) and high impact strength (˜524 J/m).

As shown in Table 6, the addition of free radical initiator(2,5-Bis(tert-butylperoxy)-2,5-dimethylhexane, in this case) in theternary blends dramatically improved the impact strength of the matrix,fabricating a super-toughened material. In a specific PLA/PBS/PBAT blendwith only 0.02 Luperox peroxide we finds as high as 996 J/m notched Izodimpact strength. However, in such formulation, the free radicalinitiator can be selected from the ones listed in Table 2, in the rangeof 0.0001 phr-15 phr by weight of the whole composites.

Table 6 also shows the effect of fillers in the composites (Glass fiber,Miscanthus fiber and Talc in these cases). The incorporation ofappropriate filler can increase the HDT of the materials dramatically(to 78° C. with glass fiber) remaining acceptable impact strength (˜140J/m) and high stiffness (˜modulus of 4.3 GPa), fabricatingtoughness—stiffness—HDT balanced bio-based composites. However, thefiller/reinforcing agent can also be selected, but not limited to, fromthe ones listed in Table 2, in the range of 0.01 to 60 wt %.

TABLE 7 The gel contents and MFI of the PLA/PBS/PBAT/Luperox ternaryblends with different Luperox contents Gel MFI MFI Testing SampleContents (g/10 min) condition Without Luperox 101 P-S10T10 0 5.45 190°C., 2.16 kg P-S20T20 0 5.0  P-S40T20 0 7.98 With Luperox 101P-S10T10-L0.3 0 8.44 230° C., 2.16 kg P-S10T10-L0.5 1.4 4.49P-S10T10-L0.75 5.4 NA P-S20T20-L0.02 0 2.83 P-S20T20-L0.3 0.6 1.12P-S20T20-L0.5 3.4 NA P-S20T20-L0.75 9 NA P-S40T20-L0.02 0 1.88P-S40T20-L0.3 0.9 0.65 P-S40T20-L0.5 4.6 NA P-S40T20-L0.75 17.5 NA

The gel contents and MFI values of the composites can be controlled bythe luperox contents, as shown in Table 7. The gel contents are wellcontrolled in our formulation by using small amount of luperox, whilekeeping high impact strength and high elongation at yield.

TABLE 8 One-step Extruded PBS/PBAT/PHBV ternary blends and theircomposites MFI Modulus Tension Elongation Elongation Flexure FlexureImpact (g/10 min) (Young's) Strength at Yield at break Modulus Strengthstrength HDT (190° C., Samples (MPa) break(MPa) (%) (%) (MPa) (MPa)(J/m) (° C.) 2.16 kg) PBS 60 769 43.1 18.03 176.2 1022 32.44 277.4 82.1115.8 PBAT 20 (61.6) (2.58) (0.18) (40.6) (51.2) (0.84) (107.5) PHBV 20 L0.3 phr PBS 40 1220 27.2 14.24 89.3 1446 29.10 129.87 82.2 22.24 PBAT 20(123.65) (0.4) (0.6) (19.03) (17.26) (0.68) (32.65) PHBV 40 L 0.3 phr

More examples of ternary blends on a combination of PHBV/PBS/PBATbiodegradable polymers and their composites are shown in Table 8. Theternary blend (without filler) with high impact strength, high HDT aswell as good flow ability (high MF), exhibits much different propertiescompared to the PLA/PBS/PBAT/Luperox composites. By controlling theamount of PHBV and Luperox, properties like MFI can be adjusted ortailored. Quaternary blends PLA/PBS/PBAT/PHBV/Luperox withsuper-toughness and high MFI are also prepared based on the abovetheory. One example on quaternary blends is given in Table 9. The MFI ofthe quaternary blends increased from ‘not flow’ to 13.5 while remainingthe acceptable impact strength.

TABLE 9 One-step Extruded PLA/PBS/PBAT/PHBV quaternary blends MFIModulus Elongation Elongation Impact (g/10 min) (Young's) Strength at atYield at break strength HDT (190° C., Samples (MPa) break(MPa) (%) (%)(J/m) (° C.) 2.16 kg) 85[PLA60/PBS20/PBAT20]- 2325 37.9 3.61 91.02 119.455.0 13.5 15PHBV-Luperox 0.3 (132.65) (1.38) (0.03) (7.69) (22.85)

Finally, the improved MFI ternary or quaternary materials can be used ininjection molding to prepare high impact products. The PBS in the matrixcan be selected from either petrol-based PBS (Tunhe PBS in this case) orbio-based PBS (BioPBS in this case). Fillers (such as talc or Miscanthusfiber) can be introduced into the matrix in process through side-stufferand corresponding composites can be fabricated. The modulus and strengthare greatly improved with the addition of fillers, from 0.4 to 1.4 GPa(Modulus) with an acceptable impact strength which can be used in manyapplications.

Composites Based on a Prepared Compatibilized Matrix

TABLE 10 The properties of the injection molding composites: HIPBSblending with other biodegradable polymers MFI Tension TensionElongation Elongation Flexure Flexure Impact (g/10 min) Modulus Strengthat Yield at break Modulus strength strength HDT (210° C., Samples (MPa)(MPa) (%) (%) (MPa) (MPa) (J/m) (° C.) 7.16 kg) HIPBS 460 47.3 27.17146.07 379 16.36 689.233 82.5 0.16 (12.64) (0.75) (0.17) (6.82) (6.8)(0.28) (47.989) Blending with PHBV 80 wt % (HIPBS)/ 846 34.5 17.02133.93 786 28.69 163.18 77.65 19.54 20 wt % PHBV (55.69) (0.35) (0.23)(0.52) (40.03) (0.85) (82.215) Blending with PLA 95 wt % HIPBS/ 660 44.720.06 121.85 541 22.69 781.58 64.92 0.28 5 wt % PLA (21.27) (0.62)(0.07) (4.87) (15.24) (0.54) (59.28) 90 wt % HIPBS/ 804 43.1 19.01132.92 658 26.9 823.05 62.90 0.38 10 wt % PLA (17.37) (0.67) (0.16)(7.18) (20.54) (0.77) (56.94) Blending with PBS 80 wt % (HIPBS)/ 62147.2 20.74 138.09 581 24.51 670.12 82.0 0.63 20 wt % PBS (11.51) (0.83)(0.16) (11.38) (6.76) (0.24) (25.60) 60 wt % (HIPBS)/ 735 47.9 20.06155.90 603 25.72 449.47 89.1 1.9 40 wt % PBS (15.92) (0.74) (0.10)(8.61) (32.21) (1.20) (38.45) Note: HIPBS = PBS 80 -PBAT 20 -Luperox0.02

The binary blends presented in these examples are based on a combinationof a prepared compatibilized super-tough (PBS80-PBAT20-Luperox 0.02 inthis case) matrix and another selected (PHBV or PLA in this case)biodegradable polymer. The matrix can also be selected from othercompatibilized super tough biodegradable polymers but not limited toPBS95-PBAT5-Luperox 0.02, PLA60-PBS20-PBAT20-Luperox0.02, et al. Thesecond biodegradable polymer can also be selected from but not limitedto PHBV, PLA, PCL, PBS, PBAT, et al. Normally biodegradable materialswith high MFI are selected. Each biodegradable polymer may vary in therange of 0.01 to 99 wt % by weight of the whole composites.

As shown in Table 10, blending prepared super-tough matrix with otherbiodegradable materials can modify the properties of the matrix. Theincorporation of PHBV, PLA or PBS can both increase the modulus of thesample, while remaining high impact strength. More notably such blendsin presence of other biodegradable polymers made most innovativebiodegradable composites with increased melt flow index (MFI) values.With introduction of 20 wt % PHBV, we could achieve an increase of MFIby ˜120 times from 0.16 to ˜19.54 g/10 min. The blending with high PBSloadings also increases the MFI of the sample while remaining highimpact strength. Meanwhile, the composites maintain high melt strengthbecause of the used super-tough matrix and zero gel content because ofthe low luperox used in preparing the matrix.

High Barrier Composites Based on a Prepared Compatibilized Matrix

TABLE 11 The water and oxygen barrier properties of the compressionsamples: HIPBS blending with different kinds of talc PermeationPermeation OTR (O2) WVTR (water) Sample (cc/m²-day) (cc · mil/m²-day)(g/m²-day) (g · mil/m²-day) HIPBS 43.0 786.6 37.3 851.6 HIPBS- 3.6 126.64.1 137.2 Talc1 HIPBS- 6.7 179.3 6.7 210.6 Talc2 HIPBS- 8.8 249.5 10.2297.8 Talc3

The water and oxygen barrier properties of the high impact PBS withdifferent talc are shown in Table 11. The polymer matrix used here issuper toughened high impact PBS, talc fillers are different kinds oftalc. The matrix can also be selected from other compatibilized supertough biodegradable polymers but not limited to PBS nano-blends, PLAternary blends or quaternary blends et, al. The filler can also beselected from but not limited to nano-clay, micro-crystal cellulose,nano cellulose fiber, Miscanthus fiber and other biomass fillers and theloading of the filler can be changed from 1 wt % to 60 wt %.

As shown in Table 11, the incorporation of the talc fillers can improvethe barrier properties of the biodegradable blends while remaining highmelt strength and toughness. Casting or blown film, thermoformingpackaging can be fabricated with high contents of fillers, ensuring thecost competitive and high barrier properties. The water barrier of theHIPBS-Talc1 is comparable to the polystyrene (PS) and oxygen barrier ofthe HIPBS-Talc1 is comparable to the polyethylene terephthalate (PET)(from the data reported by SABIC, ltd. [47]), making the composites apromising candidate in the barrier packaging industries.

It is to be understood that while the disclosure has been described inconjunction with the above embodiments, that the foregoing descriptionand examples are intended to illustrate and not limit the scope of thedisclosure. Other aspects, advantages and modifications within the scopeof the disclosure will be apparent to those skilled in the art to whichthe disclosure pertains.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs.

The embodiments illustratively described herein may suitably bepracticed in the absence of any element or elements, limitation orlimitations, not specifically disclosed herein. Thus, for example, theterms “comprising”, “including,” containing”, etc. shall be readexpansively and without limitation. Additionally, the terms andexpressions employed herein have been used as terms of description andnot of limitation, and there is no intention in the use of such termsand expressions of excluding any equivalents of the features shown anddescribed or portions thereof, but it is recognized that variousmodifications are possible within the scope of the disclosure. Thus, itshould be understood that although the present disclosure has beenspecifically disclosed by specific embodiments and optional features,modification, improvement and variation of the embodiments thereinherein disclosed may be resorted to by those skilled in the art, andthat such modifications, improvements and variations are considered tobe within the scope of this disclosure. The blends, composites,articles, methods and examples provided here are representative ofparticular embodiments, are exemplary, and are not intended aslimitations on the scope of the disclosure.

The scope of the disclosure has been described broadly and genericallyherein. Each of the narrower species and subgeneric groupings fallingwithin the generic disclosure also form part of the disclosure. Thisincludes the generic description with a proviso or negative limitationremoving any subject matter from the genus, regardless of whether or notthe excised material is specifically recited herein.

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatembodiments of the disclosure may also thereby be described in terms ofany individual member or subgroup of members of the Markush group.

All publications, patent applications, patents, and other referencesmentioned herein are expressly incorporated by reference in theirentirety, to the same extent as if each were incorporated by referenceindividually. In case of conflict, the present specification, includingdefinitions provided in this disclosure, will control.

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1. A nano-blend of two or more biopolymers comprising a nanostructuredfirst biopolymer in a matrix of a second biopolymer, wherein thenanostructured first polymer is 100 nm or less in diameter.
 2. Thenano-blend of claim 1, wherein the first biopolymer is polybutyrateadipate terephthalate (PBAT), and the second polymer is polybutylenesuccinate (PBS).
 3. The nano-blend of claim 1, wherein the firstbiopolymer is polybutylene succinate (PBS), and the second polymer ispolybutyrate adipate terephthalate (PBAT).
 4. (canceled)
 5. Thenano-blend of claim 1, wherein the nano-blend further includespolylactic acid (PLA).
 6. The nano-blend of claim 5, wherein thenano-blend comprises 60% wt. or less of PLA.
 7. The nano-blend of claim1, wherein the nano-blend further includespoly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV).
 8. The nano-blendof claim 7, wherein the nano-blend comprises 25% wt. or less of PHBV. 9.The nano-blend claim 1, wherein the nano-blend comprises 25% wt. or lessof PBAT.
 10. The nano-blend of claim 1, wherein the nano-blend comprises0.75 phr or less of a free radical initiator.
 11. (canceled)
 12. Thenano-blend of claim 1, wherein the nano-blend is a high melt flowbiodegradable composite.
 13. The nano-blend of claim 1, wherein thenano-blend is free of a functional monomer.
 14. The nano-blend of claim1, wherein the nano-blend is free of any gel content.
 15. Abiodegradable composite comprising the nano-blend of claim 1 and one ormore fillers.
 16. The biodegradable composite of claim 15, wherein thecomposite comprises up to 60% by weight of the filler.
 17. Thebiodegradable composite of claim 15, wherein the one or more fillers isselected from the group consisting: natural fibers from perennialgrasses, cellulose and agricultural residues; inorganic mineral fillers;carbon fibers; by-products (biomass fillers) from coffee, tea and otheragricultural products; and a combination thereof, and wherein theinorganic fillers include one or a combination of two or more of talc,clay and glass fiber.
 18. The biodegradable composite of claim 17,wherein the perennial grasses include one or a combination of two ormore of miscanthus, switchgrass and bamboo. 19-20. (canceled)
 21. Thebiodegradable composite of claim 15, wherein the biodegradable compositeis compostable.
 22. An article of manufacture comprising thebiodegradable composite of claim
 15. 23. An in-situ method ofmanufacturing the nano-blend of claim 1, the in-situ method comprisingmelting the first and the second biodegradable polymers in the presenceof an amount of a free radical initiator, thereby manufacturing thenano-blend.
 24. The in-situ method of claim 23, wherein the amount freeradical initiator is 0.75 phr or less. 25-29. (canceled)